Automobile manufacturers are currently concerned about lowering as much as possible the noise nuisances created by the engines of their vehicles.
Many parts can be the source of such nuisances among which the following can be given as examples: air filter boxes, engine cases, cylinder head covers, compressors of turbocompressors for supercharging, etc.
In this context, mounting acoustic devices on various internal combustion engine air circulation tubes, especially on the air intake circuit for such engines, has already been proposed.
It should in particular be noted that in supercharged internal combustion engines the compressor mounted in the air intake conduit can create aerodynamic instability phenomena causing flow rate inversions.
Now, these phenomena are sources of noises extending over a broad frequency band which are particularly bothersome and very difficult to reduce; this is even more difficult because they only appear late in the development cycle.
It is currently proposed to solve this drawback by equipping the air intake conduit of engines equipped with turbocompressors for supercharging with acoustic devices such as broad frequency band silencers or absorbing materials.
As a general rule these acoustic devices are particularly sophisticated and costly and furthermore are often insufficiently effective.